This invention concerns an injection syringe device to be utilized especially by dentists to give injections inside the mouths of their patients.
It is well known, especially for dental surgeons, that injections are very frequent surgical procedures, particularly to administer local anesthesia. A dentist, for example, would insert a hollow needle attached to an ampule of fluid which he would then inject by means of a thrust syringe. Moreover, it is known that, because of the particular nature of the tissue into which the dentist usually makes his injections, the plunger of the syringe is activated by an extremely strong plunger-fulcrum system, thus enabling the dentist to apply a strong push to the fluid in the ampule with the palm of his hand. Accordingly, syringes of this kind include a very strong metal syring holder, the plunger of which is shaped to anatomically fit in the palm of the dental surgeon's hand.
Due to the frequency of the above-mentioned surgical procedure with the minimal amounts of anesthesia injected each time, it is clear that the dental surgeon must use the same needle a number of times and also the same ampule or cartridge a number of times. There is therefore a problem in day-to-day practice concerning compliance with sterility regulations whenever the dental surgeon changes needle. It is a fact that most of the systems known today do not allow adequate compliance with stringent regulations of asepsis.
A need is therefore felt to avoid such drawbacks by creating a needle-cartridge-syringe injection device which permits very strict compliance with the regulations of asepsis when a dental surgeon carries out the normal operations related to an injection, especially when he wishes to change the needle or the cartridge of the injection device.